Variable support footwear using electrorheological or magnetorheological fluids

ABSTRACT

A variable footwear support system includes at least one rheological body within a sole of an article of footwear, control electronics within the article of footwear, and at least one E/M field generator coupled to the control electronics and arranged operably proximate to at least one rheological body. The sole is formed of a resilient material and the rheological body contains a Theological fluid having a viscosity that is variable in the presence of an energy field. The control electronics is adapted to generate at least one control signal. The at least one E/M field generator is adapted to generate an energy field corresponding to a control signal generated by the control electronics upon the rheological body.

This application also claims the benefit of U.S. Provisional Application No. 60/678,548 filed May 6, 2005, which is incorporated in its entirety herein by reference.

BACKGROUND

1. Field of Invention

Embodiments disclosed herein generally relate to articles of footwear having electronically controllable cushioning systems that are low power, low cost, and fast responding.

2. Discussion of the Related Art

Modern running and walking footwear are a combination of many elements each having a specific function which aids in the overall ability of the footwear to withstand many miles of running or walking, while providing cushioning and support for the foot and leg. Articles of athletic footwear are divided into two general parts, an upper and a sole. The upper is designed to snugly and comfortably enclose the foot, while the sole must provide traction, protection and a durable wear surface. It is often desirable to provide the footwear with a midsole having a layer of resilient, cushioning materials for enhanced protection and shock absorption when the heel strikes the ground during the stride of the wearer. This is particularly true for training or jogging footwear designed to be used over long distances or over a long period of time. These cushioning materials must be soft enough to absorb the shock created by the foot strike and firm enough not to “bottom out” before the impact of the heel strike is totally absorbed.

The typical running stride involves the runner landing on the lateral, posterior edge of the footwear in the heel region followed by pronation toward the medial side as the foot continues through its stride. As footstrike continues, the foot stops pronating and begins to supinate as the foot rocks forward so that the foot reaches a neutral position at midstance. From midstance, the foot rocks forward to the forefoot region where toe-off occurs at the ball and front of the foot. Toe-off typically involves the toes on the medial side of the foot pushing off the running surface as the foot leaves the ground to begin a new cycle.

Pronation involves the rolling of the foot from its lateral, posterior side to its inner, medial side. Although pronation is normal and necessary to achieve proper foot positioning, it can be a source of foot and leg injuries for runners who over-pronate. The typical runner who over-pronates lands on the outer lateral side of the heel in a supinated position and then rolls medially across the heel toward the inner side of the footwear beyond a point which may be considered normal. While some amount of pronation is helpful in decreasing pressure and stress experienced by the leg, excessive pronation can cause stress on various joints, bones and soft tissue. Supinating, which involves rolling of the foot from the medial to the lateral side, while not as common as over pronating, can also cause foot and leg injuries if it is excessive.

Conventional running and walking footwear are designed to provide the user with the maximum amount of available cushioning tend to sacrifice footwear stability by using a midsole cushioning system that is too soft and has too much lateral flexibility for a person who over-pronates or requires some form of motion control. The lateral flexibility and deformation of traditional cushioning materials contribute to the instability of the subtalar joint of the ankle and increase the runner's tendency to over pronate. This instability has been cited as one of the causes of “runner's knee” and other such athletic injuries. As a result, over-pronators generally do not use contemporary shoes specifically designed for maximum cushioning, but instead use heavier, firmer footwear, or footwear having motion control devices specifically designed to correct physical problems such as excessive pronation. Motion control devices limit the amount and/or rate of subtalar joint pronation immediately following foot strike.

Various ways of resisting excessive pronation or instability of the subtalar joint have been proposed and incorporated into running footwear as motion control devices. In general, these devices have been fashioned by modifying conventional footwear components, such as the heel counter, and/or the midsole cushioning materials. Conventional solutions provide a constant stiffness and fixed level of support that presses against the medial side of the foot, limiting internal rotation of the ankle. Examples of such devices include: U.S. Pat. No. 5,046,267, to Kilgore et al.; U.S. Pat. No. 5,155,927, to Bates et al.; and U.S. Pat. No. 5,367,791, to Gross et al.

Footwear systems have been designed that employ fluid bladder systems for providing desirable resilience characteristics. For example, U.S. Pat. App. Pub. No. 2002/0053146, entitled “Article of footwear with a motion control device,” which is hereby incorporated by reference, discloses a bladder system for footwear in which fluid flow from one chamber to another chamber within the shoe is used to define the stiffness characteristic of the shoe. This system is superior to typical shoes in that it provides stiffness that varies based upon how pressure is applied by the user. On the other hand, this system has the significant drawback of being fixed by its physical design, not allowing variation in how the stiffness varies based upon differences in the physical activity being performed by the user. Users of athletic shoes often engage in a number of physical activities including walking, running, jumping, and landing. Due to its physical design, however, the aforementioned fluid bladder system accommodates all of these diverse physical activities with the same physical response. In this way it provides a fixed stiffness characteristic for the wearer in much the same way that a typical shoe does.

Other attempts have been made to provide support and comfort in an article footwear by incorporating bladders in fluid communication with each other within a sole. Examples of such devices are found in U.S. Pat. App. Pub. No. 2002/0053146 as well as in U.S. Pat. No. 4,183,156 to Rudy, which is incorporated herein by reference; U.S. Pat. No. 4,446,634 to Johnson et al.; U.S. Pat. No. 4,999,932 to Grim; Austrian Patent No. 200,963 to Schutz et al.; and HYDROFLOW, by BROOKS Sports, Inc. As with U.S. Pat. App. No. 2002/0053146, these prior art systems do not allow for variation in how the stiffness varies based upon differences in the physical activity being performed by the user. In this way these devices provide a fixed stiffness characteristic for the wearer in much the same way that a typical shoe does. Moreover, while such prior art systems, act to moderate the amount of motion control, they do so using heavy, bulky footwear, which is weighted down by support features, and designed for the severe over-pronator.

SUMMARY

Several embodiments disclosed herein address the needs above as well as other needs by providing a variable support footwear using electrorheological (ER) or magnetorheological (MR) fluids.

One embodiment exemplarily disclosed herein provides a variable footwear support system that includes at least one rheological body within a sole of an article of footwear, control electronics within the article of footwear, and at least one E/M field generator coupled to the control electronics and arranged operably proximate to at least one rheological body. The sole is formed of a resilient material and the rheological body contains a rheological fluid having a viscosity that is variable in the presence of an energy field. The control electronics is adapted to generate at least one control signal. The at least one E/M field generator is adapted to generate an energy field corresponding to a control signal generated by the control electronics upon the rheological body.

Another embodiment exemplarily disclosed herein provides a variable footwear support method that includes steps of receiving sensor data from at least one sensor, generating at least one control signal based on the received sensor data, and energizing at least one E/M field generator based on the at least one generated control signal. The sensor data describes at least one of an intensity and a frequency of foot-falls of a wearer of an article of footwear. Each energized E/M field generator is adapted to generate an energy field upon at least one rheological body arranged within a sole of an article of footwear. The sole is formed of a resilient material and wherein the at least one rheological body contains a rheological fluid having a viscosity that is variable in the presence of the generated energy field.

Yet another embodiment exemplarily disclosed herein provides a variable footwear support method that includes steps of receiving user input from a user interface, generating at least one control signal based on the received user input, and energizing at least one E/M field generator based on the at least one generated control signal. Each energized E/M field generator is adapted to generate an energy field upon at least one rheological body arranged within a sole of an article of footwear. The sole is formed of a resilient material and wherein the at least one rheological body contains a rheological fluid having a viscosity that is variable in the presence of the generated energy field.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of several embodiments disclosed herein will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings.

FIG. 1 illustrates an exploded view of an article of footwear incorporating a bladder system according to one embodiment;

FIG. 2 illustrates a top view of one embodiment of a bladder system; and

FIG. 3 illustrates a top view of one embodiment of a cushioning system.

Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments exemplarily disclosed herein. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments exemplarily disclosed herein.

DETAILED DESCRIPTION

The following description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of exemplary embodiments. The scope of the invention should be determined with reference to the claims.

FIG. 1 illustrates an exploded view of an article of footwear incorporating a bladder system filled with MR or ER fluid, according to one embodiment. FIG. 2 illustrates a top view of the bladder system shown in FIG. 1, in accordance with one embodiment.

Referring to FIG. 1, an article of athletic footwear 80 is comprised of an upper 75 for covering a wearer's foot and a sole assembly 85. The upper 75 can include a sock liner 70 can be placed therein. The sole assembly 85 includes the bladder system 10, a midsole layer 60, and an outsole layer 65.

The outsole layer 65 is adapted to engage the ground and is secured to at least a portion of midsole layer 60. Depending upon the material forming the midsole layer 60 and upon the performance demands of the shoe 80, midsole layer 60 can also form part or all of the ground engaging surface so that part or all of outsole layer 65 can be omitted. The bladder system 10 is located in the heel region 81 of footwear 80 and is incorporated into the midsole layer 60 by any conventional technique such as foam encapsulation or placement in a cut-out portion of a foam midsole. A suitable foam encapsulation technique is disclosed in U.S. Pat. No. 4,219,945 to Rudy, hereby incorporated by reference.

As illustrated in FIGS. 1 and 2, the bladder system 10 includes a lateral bladder chamber 12, a medial bladder chamber 14, and a central bladder chamber 16. The central bladder chamber 16 is positioned between, and is in fluid communication with lateral and medial bladder chambers 12, 14, respectively, via conduits 27. According to various embodiments, a rheological fluid (e.g., an electrorheological (ER) fluid that exhibits a change in its ability to flow or shear in the presence of an electric field or a magnetorheological (MR) fluid that exhibits a change in its ability to flow or shear in the presence of a magnetic field, respectively) is contained within the bladder chambers and conduits of the bladder system 10. Accordingly, a bladder chamber containing rheological fluid, or a conduit through which the rheological fluid flows, may be referred to as a “rheological body.”

As disclosed in U.S. Pat. No. 6,852,251, which is incorporated in its entirety herein by reference, ER fluids are colloidal suspensions whose rheological properties can be varied through the application of an external electric field, enabling variable viscosity under electronic control. Under the application of a field of the order of 1-2 kV/mm, an ER fluid can exhibit a solid-like behavior, such as the ability to transmit sheer stress. This transformation from liquid-like to solid-like behavior can be very fast, on the order of 1 to 10 ms, and is reversible when the electric field is removed. U.S. Pat. No. 5,271,858 relates to an ER fluid that includes esters and amides of an acid of phosphorus and is also incorporated in its entirety herein by reference.

As disclosed in U.S. Pat. No. 5,906,767, which is incorporated in its entirety herein by reference, MR fluids undergo a change in viscosity in the presence of a magnetic field. MR fluids typically include magnetic-responsive particles dispersed or suspended in a carrier fluid. In the presence of a magnetic field, the magnetic-responsive particles become polarized and are thereby organized into chains of particles or particle fibrils within the carrier fluid. The chains of particles act to increase the apparent viscosity or flow resistance of the overall materials resulting in the development of a solid mass having a yield stress that must be exceeded to induce onset of flow of the MR fluid. The force required to exceed the yield stress is referred to as the “yield strength”. In the absence of a magnetic field, the particles return to an unorganized or free state and the apparent viscosity or flow resistance of the overall materials is correspondingly reduced. Such absence of a magnetic field is referred to herein as the “off-state”. MR fluids are also described in U.S. Pat. Nos. 5,382,373, 5,578,238, 5,599,474 and 5,645,752, each of which are incorporated in their entirety herein by reference. These patents mention that phosphate esters, in general, can be used as surfactants in MR fluids. U.S. Pat. No. 5,645,752 describes an exemplary MR fluid that includes a polyoxyalkylated alkylaryl phosphate ester.

Referring next to FIG. 2, the bladder system 10 includes one or more electro/magnetic (E/M) field generators disposed operably proximate to respective ones of the conduits 27 that, when energized, generate electronically controllable electric or magnetic fields upon fluid flowing within respective conduits 27. Exemplary regions in which E/M field generators can be disposed operably proximate to conduits 27 are identified at cross-hatched areas 28. When ER fluid is contained within the bladder system 10, each E/M field generator may be provided as a single electrode or multiple electrodes (e.g., disposed in a ring arrangement around a corresponding conduit 27 or in any other physical arrangement). In one embodiment, an electrode-based E/M field generator may be provided as described in U.S. Pat. No. 6,378,558, which is incorporated in its entirety herein by reference, wherein an E/M field generator includes a coaxial cylinder of electrodes or arrangement of parallel plates between which ER fluid flows. Due to an electric voltage applied to the electrodes, the viscosity of the ER fluid located between the electrodes and therewith the through-flow resistance through the valve gap is controllable, thereby modulating the rate of fluid flow. Similarly, when MR fluid is contained within the bladder system 10, each E/M field generator may be provided as a single electromagnet or multiple electromagnets (e.g., disposed in a ring arrangement around a corresponding conduit 27 or in any other physical arrangement). In one embodiment, the flow of MR fluid can be controlled as described in U.S. Pat. No. 5,452,745, which is incorporated in its entirety herein by reference, wherein the flow of MR fluid is controlled by energizing electromagnets located near or around a valve or orifice such that a magnetic field is applied to the MR fluid as it flows past. The interaction between ferromagnetic particles in the MR fluid increases the effective viscosity of the MR fluid. This change in viscosity causes the resistance to the fluid flowing through the valve or orifice to increase, and causes a proportional change in the inlet pressure to the valve, thereby slowing or stopping the fluid flow.

As used herein, an “ER valve” or an “MR valve” (generically referred to as an “E/M valve”) refers to the combination of a conduit 27 filled with ER fluid or MR fluid, respectively, and a corresponding E/M field generator operably proximate to the conduit 27 (e.g., within a respective cross-hatched area 28). Accordingly, depending on the degree to which an E/M field generator is energized, an E/M valve can be fully “opened” (e.g., as when an E/M field generator is not energized), fully “closed” (e.g., as when an E/M field generator is fully energized), or partially opened/closed (i.e., modulated).

Bladder chambers 12, 14, 16 and conduits 27 may be formed of a thermoplastic elastomeric barrier film such as polyester polyurethane, polyether polyurethane, a cast or extruded ester based polyurethane film having a shore “A” hardness of 80-95, e.g., Tetra Plastics TPW-250. Other suitable materials can be used such as those disclosed in the '156 patent to Rudy. Specific examples of thermoplastic urethanes that may be used to form the bladder chambers 12, 14, 16 and conduits 27 include urethanes such as Pellethane™, (a trademarked product of the Dow Chemical Company of Midland, Mich.), Elastollani® (a registered trademark of the BASF Corporation) and ESTANE® (a registered trademark of the B.F. Goodrich Co.), all of which are either ester or ether based and have proven to be particularly useful. Thermoplastic urethanes based on polyesters, polyethers, polycaprolactone and polycarbonate macrogels can also be employed. Further suitable materials also include thermoplastic films containing crystalline material, such as disclosed in U.S. Pat. Nos. 4,936,029 and 5,042,176 to Rudy, which are incorporated by reference; polyurethane including a polyester polyol, such as disclosed in U.S. Pat. No. 6,013,340 to Bonk et al., which is incorporated by reference; or a multi-layer film formed of at least one elastomeric thermoplastic material layer and a barrier material layer formed of a copolymer of ethylene and vinyl alcohol, such as disclosed in U.S. Pat. No. 5,952,065 to Mitchell et al., which is incorporated by reference. In one embodiment, bladder chambers 12, 14, 16 and conduits 27 are integrally formed of first and second sheets of elastomeric barrier film. In another embodiment, bladders 12, 14, 16 are formed from generally transparent or translucent elastomeric film to enable visibility through the bladders of the ER or MR fluid within.

U.S. Pat. No. 4,183,156 ('156) and U.S. Pat. No. 4,219,945 ('945) to Marion F. Rudy, the contents of which are hereby expressly incorporated by reference, describe conventional welding techniques which can be used to form the shapes of the bladder chambers 12, 14, 16 and conduits. As disclosed in the '156 and '945 patents, sheet 40 and 45 can be welded to one another to define the side walls of bladder chambers 12, 14, 16 and conduits, as well as interior welds (not shown in the drawings) within the bladder chambers to maintain the bladder chambers in a generally flat configuration. In another embodiment, bladder chambers 12, 14, 16 and conduits are formed using conventional blow-molding techniques.

Bladder chambers 12, 14, 16 can be sealed to hold MR or ER fluid. The fluid can be placed in the bladder through an inflation tube (not shown) in a conventional manner by means of a needle or hollow welding tool. After being filled with fluid, the bladder can be sealed at the juncture of the bladder and inflation tube, or by the hollow welding tool around the inflation point on the inflation tube.

In one embodiment, one or more additional conduits (i.e., valves) with fixed flow characteristics can be used in combination with the aforementioned E/M valves. For example, a one-way valve with fixed flow characteristics may be used in serial combination with an E/M valve to prevent backflow through any passages that are intended to only allow flow in one direction. These one-way valves may be set to open when the differential pressure between two bladders reaches a predetermined level.

In one embodiment, pressure sensors (not shown) may be provided within one or more bladder chambers to detect pressure levels, pressure changes within and/or pressure differentials between bladder chambers of the bladder system 10 and generate corresponding sensor data. In one embodiment, the pressure sensors may be electronically connected to control electronics (not shown) on board the shoe 80 (e.g., incorporated within the midsole layer 60. In one embodiment, the control electronics of each shoe may include a local microprocessor that is electrically connected to each pressure sensor and is adapted to receive the sensor data. Software running upon the microprocessor can process the received sensor data to perform conditional logic based upon the magnitudes of and/or changes in magnitude of the sensor data. In one embodiment, each E/M field generator is energized to generate an electric or magnetic field based upon electric current output by power electronics. In one embodiment, the power electronics is connected to the control electronics, wherein the control electronics controls the level of electric current output by the power electronics. In one embodiment, the control electronics controls the power electronics in accordance with the received sensor data. Having generally described an active suspension shoe in accordance with numerous embodiments of the present invention above, an exemplary process by which E/M field generators are selectively energized will now be described.

Prior to the heel of a user touching down, a nominal pressure in the bladder chambers is detected by one or more pressure sensors provided within central bladder chamber 16. Information within the sensor data generated by such a pressure sensor is transmitted to the microprocessor and saved by software running on the microprocessor as a nominal pressure variable (e.g., P_NOMINAL). Initial striking of the heel increases the pressure within the central bladder chamber 16. The increase in pressure is detected by one or more pressure sensors within one or more bladder chambers in the heel as a result of chamber deformation. In one embodiment, the total amount of information within the sensor data generated by each pressure sensor is transmitted to the microprocessor and saved by software running on the microprocessor as a single pressure variable (e.g., P_STRIKE), regardless of how many pressure sensors generate the pressure data. In another embodiment, information within the sensor data generated by each pressure sensor is transmitted to the microprocessor and is saved by software running on the microprocessor as multiple pressure variables, one for each bladder chamber within which a pressure sensor is provided (e.g., P_STRIKE_LEFT, P_STRIKE_CENTER, and P_STRIKE_RIGHT). Based upon the absolute and/or relative pressure levels within the one or more chambers as detected by the one or more pressure sensors, the microprocessor controls the power electronics to modify the level of current output to one or more of the E/M field generators. The magnitude of current output to each E/M field generator affects the magnitude of the electric or magnetic field that is generated within the conduit 27. The magnitude of the electric or magnetic field that is generated within the conduit 27 affects the flow rate of ER or MR fluid through the conduit 27 between bladder chambers. Accordingly, by controlling the level of current that is output by the power electronics, the flow rate of ER or MR fluid through the conduit 27 between bladder chambers can be controllably adjusted.

By controllably adjusting the flow rate of ER or MR fluid into and/or out of certain bladder chambers, varying degrees of cushioning and support within the sole assembly 85 can be achieved. For example, by allowing faster fluid flow from the central bladder chamber 16 to the medial bladder chamber 14 than is allowed from the central bladder chamber 16 to the lateral bladder chamber 12, greater support is provided to the wearer on the medial side of the shoe 80 and greater cushioning is provided to the wearer on the lateral side of the shoe 80. Alternately, by allowing faster fluid flow from the central bladder chamber 16 to the lateral bladder chamber 12 than is allowed from the central bladder chamber 16 to the medial bladder chamber 14, greater support is provided to the wearer on the lateral side of the shoe 80 and greater cushioning is provided to the wearer on the medial side of the shoe 80. Similar control methods can be provided between chambers in the heel and chambers in the forefoot of the shoe. For example, allowing faster fluid flow from a medial bladder chamber in the heel of the shoe 80 to a medial bladder chamber in the forefoot of the shoe 80 than fluid flow from a lateral bladder chamber in the heel of the shoe 80 to a lateral bladder chamber in the forefoot of the shoe 80 will result in greater cushioning at the medial heel and greater support at the lateral heel. Alternately, allowing faster fluid flow from a lateral bladder chamber in the heel of the shoe 80 to a lateral bladder chamber in the forefoot of the shoe 80 than fluid flow from a medial bladder chamber in the heel of the shoe 80 to a medial bladder chamber in the forefoot of the shoe 80 will result in greater cushioning at the lateral heel and greater support at the medial heel.

In addition to varying the ratio of flow rates among the chambers on the lateral side with flow rates among chambers on the medial side, the total rate between flow from multiple heel chambers to multiple forefoot chambers may be controlled to control the overall cushioning on the heel of the wearer. Thus, both the total cushioning level as well as the relative cushioning ratio between lateral and medial sides can be varied by the microprocessor controlling the current to the E/M field generators.

In one embodiment, a user may engage a user interface to manually enter user input, the user input adapted to adjust stiffness/cushioning characteristics of the sole assembly 85 and/or modify the function by which the control electronics opens, closes, or otherwise modulates the E/M valves. In one embodiment, the user interface may be incorporated within the shoe 80 and be electrically connected to the control electronics. In another embodiment, the user interface may be incorporated within a handheld computing device (e.g., a personal digital assistant (PDA), a handheld wireless telephone, a handheld portable gaming system, a handheld portable music player, or the like) adapted to communicate with the control electronics (e.g., via a wireless connection between the shoe 80 and the handheld computing device). In one embodiment, each shoe 80 includes wireless transceiver connected to the control electronics, wherein the wireless transceiver is adapted to enable bidirectional communication with a remote processor aboard the handheld computing device. Accordingly, each wireless transceiver may be enabled using a Bluetooth protocol and support interaction with any Bluetooth-enabled remote processor. Moreover, the remote processor can be provided with Bluetooth support and local software configured to interface with, control, and configure the control electronics of each shoe 80.

In one embodiment, the control electronics of each shoe opens, closes, or otherwise modulates each E/M valve in accordance with one or more control algorithms. Accordingly, the user interface may be engaged by the user and receive user input that identifies one or more control algorithms, selected by the user, to be implemented by the control electronics. For example, if the user is going jogging, the user can engage the user interface (e.g., via a menu system supported by the user interface) to select one or more control algorithms optimized for jogging. The control electronics of each shoe may then open, close, or otherwise modulate one or more E/M valves of a respective shoe in accordance with the one or more selected control algorithms optimized for jogging. In the example above, if the user wanted to walk after jogging, the user can engage with the user interface to select one or more different control algorithms (e.g., algorithms optimized for walking as opposed to jogging). The control electronics of each shoe may then open, close, or otherwise modulate one or more E/M valves of a respective shoe in accordance with the one or more selected control algorithms optimized for walking.

In one embodiment, the handheld computing device includes local memory for storing a plurality of selectable control algorithms. Once selected by the user via the user interface, the control algorithms can be uploaded to the control electronics of each shoe (e.g., via the wireless transceiver). In such an embodiment, the control electronics of each shoe may include a local microprocessor that is adapted to receive the one or more uploaded control algorithms, store the one or more received control algorithms in a local memory, and output control signals to the power electronics, wherein the output control signals are adapted to open, close, or otherwise modulate the predetermined E/M valves based on the one or more selected control algorithms.

In another embodiment, the control electronics of each shoe includes a local memory adapted to store a plurality of selectable control algorithms. Accordingly, once user input is received from a user engaging the user interface, the handheld computing device outputs a corresponding control command to the control electronics of each shoe (e.g., via the wireless transceiver), wherein the control command identifies one or more control algorithms stored within the local memory. In such an embodiment, the control electronics of each shoe may include a local microprocessor that is adapted to receive the control command and output control signals to the power electronics, wherein the output control signals are adapted to open, close, or otherwise modulate the predetermined E/M valves based on the one or more control algorithms identified by the control command.

In yet another embodiment, the control electronics of each shoe may include a local microprocessor that is adapted to receive sensor data and/or timing data and output control signals to the power electronics, wherein the output control signals are adapted to open, close, or otherwise modulate the predetermined E/M valves based on physical activities the user is currently engaged in and/or based on particular gait characteristics of the user.

A plurality of different control algorithms can be stored either within the handheld computing device or within the local memory of the control electronics aboard the shoe itself. In one embodiment, control algorithms can be optimized with respect to different activities such as walking, jogging, running, basketball, tennis, hiking, climbing stairs, and the like, and combinations thereof. In addition, control algorithms can be optimized with respect to certain aspects of a physical activity (e.g., optimized with respect to running for speed, running for distance, jumping for height, pivoting dexterity, and the like). Moreover, control algorithms can be optimized with respect to certain ground surfaces (e.g., optimized with respect to jogging on asphalt, running on grass, walking on sidewalks, hiking on trails, and the like). Further, control algorithms can be optimized with respect to the gait styles of individual users. For example, a particular user might have one control algorithm optimized with respect to hiking on trails, a different control algorithm optimized with respect to running on asphalt, a different control algorithm optimized with respect to playing tennis, and a different control algorithm optimized with respect to walking on city sidewalks.

A user who does not over-pronate generally will put less initial pressure on the lateral side of the footwear and will force less fluid, if any, into bladder chambers 16 and 14 during a typical stride as compared to an over-pronator having the same striking force. For such a user, a control algorithm implemented within a shoe may, for example, send less current to the valve on the lateral side of the footwear than to the valves on the medial side of the footwear, allowing more fluid flow from the chamber on the lateral side because extra support is not needed to counter over pronation. For such a user, more support is thereby provided on the medial side. After the landing phase of running is over, equilibrium or initial pressure between the bladders is re-established before the next heel strike, either by opening the valves fully (by dropping and/or eliminating the current to the electrodes or electromagnets) or through the use of passive one-way valves that allows fluid to pass back into the central and lateral bladder chambers. In one embodiment, the recovery time may be approximately 1 second. The recovery time can be controlled by the control electronics based upon how much current is sent to the E/M valves during the recovery period.

A user who does over-pronate generally will put more initial pressure on the lateral side of the footwear and will force more fluid into bladder chambers 16 and 14 during a typical stride as compared to a non-over-pronator having the same striking force. For such a user, the control algorithm implemented within the shoe may, for example, send more current to the valve on the lateral side of the footwear than to the valves on the medial side of the footwear, allowing less fluid flow from the chamber on the lateral side because extra support is needed to counter over-pronation. For such a user, more support is thereby provided on the lateral side. After the landing phase of running is over, equilibrium or initial pressure between the bladders is re-established before the next heel strike, either by opening the valves fully (by dropping and/or eliminating the current to the electrodes or electromagnets) or through the use of passive one-way valves that allows fluid to pass back into the central and lateral bladder chambers. The recovery time can be controlled by the control electronics based upon how much current is sent to the E/M valves during the recovery period.

FIG. 3 illustrates a top view of one embodiment of a cushioning system.

Referring to FIG.3, a cushioning system 100 can extend along the length of footwear 80 (e.g., with one or more bladder chambers in the heel region and one or more bladder chambers in the forefoot region). Cushioning system 100 includes a bladder system 110. Bladder system 110 is constructed the same as bladder system 10, with similar components labeled with like numbers as bladder system 10, but in the 100 series of numbers. Accordingly, bladder chambers 112, 114 and 116 function in the same way as bladder chambers 12, 14 and 16, respectively.

Cushioning system 100 also includes chambers 152 and 156 in the forefoot region 150 to provide lateral stability and increased performance when running or jumping. Bladder chambers 152 and 156 extend along the forefoot region of footwear 80 and are formed of the same material as bladder chambers 12, 14 and 16. In one embodiment, bladder chambers 152 and 156 may be in fluid communication with each other by one or more conduits 127 with one or more E/M field generators operably proximate to one or more respective conduits 127 (e.g., disposed within cross-hatched areas 158) to selectively stiffen one side of the forefoot of footwear 80 during a foot stride. Bladder chambers 152 and 156 may also be in fluid communication with one or more heel chambers by one or more conduits 127 with one or more E/M field generators operably proximate to one or more respective conduits 127 (e.g., disposed within cross-hatched areas 158) to selectively stiffen one of the forefoot or heel region of the shoe.

In one embodiment, the E/M valves can be effectively controlled when the one or more control algorithms are implemented in conjunction with sensed pressure differentials between chambers in the determination of when and how strongly to energize the valves. Based upon the pressure differential between lateral and medial chambers and/or the pressure differential between a forefoot and heel chambers, fluid flow rates can be controlled using the E/M field generators to selectively stiffen various regions of the shoe including the lateral heel, the medial heel, the lateral forefoot, and/or the medial forefoot.

It will be appreciated that a bladder system can be constructed with more or less chambers than shown in FIGS. 2 and 3 depending upon the degree of control desired. For example, a bladder system may include a single heel chamber and a single forefoot chamber, both filled with MR or ER fluid, a single conduit in fluid communication with the single heel and forefoot chambers to allow fluid to flow between the chambers when pressure is applied, one or more E/M field generators arranged operably proximate to the conduit to influence the viscosity of the MR or ER fluid that flows past.

In such a two-bladder chamber embodiment, when pressure is applied to the sole such that the heel chamber experiences greater pressure than that forefoot chamber, fluid will flow from the heel to the forefoot and the rate of the flow can be electronically controlled by energizing the one or more E/M field generators. If the rate is slow as a result of a high viscosity being induced in the MR or ER fluid, the heel will be stiff. If the rate is fast as a result of low viscosity being induced in the MR or ER fluid, the heel will be compliant. If the rate is controlled to be somewhere between slow and fast, the heel will have an intermediate level of compliance. The E/M field generators can be energized at varying levels during a single stride based upon sensor readings for highly controllable stiffness profiles. For example, a pressure sensor within the heel can sense pressure levels within the heel chamber and generate sensor data. The output sensor data is used by a local microprocessor of the control electronics to output a control signal, wherein the control signal is adapted to modulate power applied to the one or more E/M magnets based upon the sensed pressure levels. In this way, the stiffness of the heel can be varied independently of the stiffness of the forefoot during a single stride based upon one or more pressure sensor readings during the execution of the stride.

In the two-bladder chamber embodiment described above, when pressure is applied to the sole such that the forefoot chamber experiences greater pressure than that heel chamber, fluid will flow from the forefoot to the heel, the rate of the flow being electronically controllable by energizing the electrodes or electromagnets. If the rate is slow as a result of a high viscosity being induced in the MR or ER fluid, the forefoot will be stiff. If the rate is fast as a result of low viscosity being induced in the MR or ER fluid, the forefoot will be compliant. If the rate is controlled to be somewhere between slow and fast, the forefoot will have an intermediate level of compliance. The E/M field generators can be energized at varying levels during a single stride based upon sensor readings for highly controllable stiffness profiles. For example, a pressure sensor within the forefoot can sense pressure levels within the forefoot chamber and generate sensor data. The output sensor data is used by the local microprocessor to output a control signal, wherein the control signal is adapted to modulate power applied to the one or more E/M magnets based upon the sensed pressure levels. In this way, the stiffness of the forefoot can be varied independently of the stiffness of the heel during a single stride based upon one or more pressure sensor readings during the execution of the stride.

In an exemplary implementation, a control algorithm optimized for a walking activity can be set such that one or more E/M field generators are energized at a high level when the pressure in the heel is greater than the pressure in the forefoot, thereby providing a stiff heel. Further, the control algorithm optimized for the walking activity can be set such that one or more E/M field generators are energized at a low level when the pressure in the forefoot is greater than the pressure in the heel, thereby providing a compliant forefoot. In another exemplary implementation, a control algorithm optimized for a jumping activity can be set such that one or more E/M field generators are energized at a low level when the pressure in the heel is greater than the pressure in the forefoot, thereby providing a compliant heel for soft landings. Further, the control algorithm optimized for the jumping activity can be set such that one or more E/M field generators are energized at a high level when the pressure in the forefoot is greater than the pressure in the heel, thereby providing a stiff forefoot for firm takeoffs.

In one embodiment, the user can engage a user interface (e.g., by accessing a button or dial) to alter the current flowing to one or more E/M field generators during some portion of a stride. For example, when the user is out for a slow walk, he or she may desire a firm heel and thus adjust the control algorithms to provide a stiff heel. Later, that same user may decide to jog and may want additional cushioning in the heel and thus press a button or turn a knob to alter the control algorithm to provide a more compliant heel. As described above, the user interface may be mounted on the shoe itself or may be incorporated within a handheld computing device that wirelessly communications with the shoes. In one embodiment, the user interface can be engaged to adjust both shoes (i.e., left and right) simultaneously because, in most instances, the user will want both shoes to be provided with the same cushioning characteristics. In another embodiment, the user interface can be engaged to each shoe individually.

In one embodiment, the current flowing to one or more E/M field generators may be altered automatically, without the need for user to engage a user interface. In such an embodiment, each shoe includes one or more sensors adapted to detect the intensity and frequency of foot-falls and generate corresponding sensor data and a local microprocessor adapted to receive usage data from the one or more sensors, to determine a present usage mode based on the received sensor data, and to adjust the stiffness/cushioning characteristics in real time to optimize performance with respect to the determined present usage mode.

In one embodiment, one or more sensors may be provided as an accelerometer (e.g., a solid state accelerometer from Analog Devices). In another embodiment, one or more sensors may be provided as a pressure sensor (e.g., provided within the midsole layer 60 of a shoe). In another embodiment, one or more sensors may be provided as a contact switch or pressure switch that can be closed with each footfall (note, contract/pressure switches would give frequency, but not strength, of each footfall).

Using the sensor data from sensors incorporated within each shoe, the local microprocessor controls current applied to the E/M field generators to adjust the stiffness of the resilient underside to achieve improved performance and/or comfort in the present athletic task. To achieve this, the local microprocessor performs real-time analysis on the usage data to determine the present usage mode of the user (e.g., to determine whether the user is walking, jogging, running, etc.). In one embodiment, the local microprocessor performs real-time analysis on the usage data to determine particular stages of a determined usage mode (e.g., to determine whether the user is about to jump, whether the user is currently jumping and is in the air, etc.). The local microprocessor can then adjust the stiffness/cushioning characteristics in real time to optimize performance with respect to the identified present usage mode. For example, upon determining that a user is about to jump (based upon usage data), the local processor can stiffen the shoe's resilient underside. Then, when the shoe is airborne, the local microprocessor can predict that a landing is imminent and un-stiffen the shoes resilient underside.

The local microprocessor can differentiate between usage modes such as walking, jogging, and running based on sensor data indicating, for example, a time delay between foot falls and/or the strength of foot falls, as generated by the sensors such as those described above. The more rapid the sequence of foot falls, the faster the user is moving. The stronger the pressure (or acceleration) signals at each foot fall, the more intense the physical activity. Based upon the sensor data, the local microprocessor can adjust the stiffness of the resilient underside. The shoe can have a number of pre-programmed mappings (as described previously) that the user can select between so that the modulation for a given physical activity is what the particular user desires.

In many sports (e.g., basketball, volleyball, etc.) players are continually jumping and landing. They may want to achieve maximum height and be optimally cushioned upon return. When an athlete jumps, the muscles in his leg, ankle, and foot stiffen to provide maximum thrust. When an athlete lands from a jump, the muscles in his leg, ankle, and foot relax to provide optimized cushioning. Similarly, the bladder system described above can be actively controlled to adjust the stiffness of the resilient underside by energizing one or more E/M field generators at the moment of jumping, to stiffen the resilient underside when the user's muscles stiffen, and then relax the resilient underside when the user lands, to provide a highly cushioned landing. An exemplary process by which such stiffening and cushioning can be achieved will now be described in greater detail below. The local microprocessor may continually poll the sensors in a given shoe. When the microprocessor detects a sensor reading that has exceeded a particular threshold value of downward pressure on the shoe, the microprocessor can infer that a jump is in progress and can energize one or more appropriate E/M field generators (e.g., in one or more portions of the shoe) to a high level of current to provide for maximum thrust during the launching stage of the jump. When the microprocessor detects a sensor reading that indicates the pressure has suddenly dropped to near-zero, the microprocessor can infer that the shoe is now airborne and that the next impact seen by the shoe will be a landing. The microprocessor can then drop the current applied to one or more E/M field generators (e.g., in one or more portions of the shoe) to optimally cushion the impending landing. In this way, the user can have real-time modification of the stiffness of the resilient underside of his/her shoe, accommodating differently for the liftoff and landing phases of a jump.

Each stride of a running athlete can be treated as a jump (e.g., liftoff, airborne, then landing) by the local microprocessor. In this way, the jumping method described in the paragraph above could be used not just for vigorous jumps in a basketball game but also during every stride of general running. In such a mode the degree of change in stiffness is likely varied at a lesser level than in vigorous jumping, but the basic method is the same.

In one embodiment, each shoe has its own local microprocessor and can be independently adjusted. In another embodiment, the two microprocessors have a wireless link between them, to allowing the shoes to coordinate in real time. For example, sensor data and/or timing data and/or status data of one shoe can be exchanged with the other shoe to coordinate jumping, landing, and other stride-based changes to the resilience of the other shoe.

As discussed above, each shoe may include one or more sensors and a microprocessor. In another embodiment, each shoe may include a wireless link enabling wireless communication of data between shoes and/or wireless communication of data with a user interface incorporated within a handheld computing device. In another embodiment, usage mode algorithms may be implemented in conjunction with the local microprocessor to determine current usage modes of the user.

In one embodiment, the local microprocessor, using the sensors as described above, can log data describing the physical activity of the user. The logged data may include information describing the number of foot falls, the time between foot falls, the rate of foot falls, the intensity at the launch point of a stride or jump, the intensity upon landing from a launch or jump, and/or the airtime between launching and landing a jump. The logged data can then be used by a user to better understand his performance and possibly work to improve. For example, an athlete may use logged data to work to minimize the intensity of force upon landing from jumps by better cushioning with his/her knees. In another example, an athlete may use the logged data to work to lengthen his or her stride for more efficient running. In another example, an athlete may use the logged data (e.g., describing pressure differentials between lateral and medial sides of a foot) to determine and document over-pronating or under-pronating events. In one embodiment, data logged by the local microprocessor of a shoe can be output to a host computer (e.g., a personal computer, a handheld computer such as a PDA, etc.) by a temporary wire connection or wireless link.

In one embodiment, the logged data can be output to a computer at the end of a session (e.g., after a user has finished walking, jogging, running, jumping, etc.). In another embodiment, the logged data can be output to a computer in real time as the sensors generate the sensor data. For example, and in one exemplary implementation, a user may be doing an aerobics workout and sensor data describing their footfall can be output to a host computer running an aerobics workout software package. The aerobics workout software package may be adapted to moderate the workout of the user in real-time based upon the generated sensor data. Accordingly, aerobics workout software package may quantify the user's performance and ask the user to increase their rate, increase their force, or make any other modifications to tune the aerobic workout. The aerobics workout software package might also identify poor gate posture (e.g., over-pronation) by displaying a warning graphic or emitting a warning sound through user interface of the host computer. In another exemplary implementation, a user may be engaged with an entertainment software package (e.g., a video game) and sensor data describing their footfall can be output to a host computer running an entertainment software package. Accordingly, the sensor data may be used as an interfacing means of controlling characters (i.e., Avatars) within an environment supported by the entertainment software package.

According to numerous embodiments exemplarily described above, the stiffness/cushioning characteristics of the resilient underside portion of a shoe can be electrically modified based upon the physical activity of the wearer so as to further enhance user performance. In one embodiment, an athletic shoe can be designed in which the stiffness of the sole assembly can be adjusted, under electronic control, based upon the type and intensity of the physical activity being performed by the wearer. In another embodiment, the stiffness of the sole assembly can be adjusted using one or more low-power E/M field generators having a fast response period enabling a wide range of stiffness values to be commanded with rapid response using low power electronics. In another embodiment, each shoe may include one or more sensors and control electronics coupled to the one or more sensors, the control electronics adapted to automatically adjust the stiffness of the sole assembly appropriately during periods of activity and thereby enhance comfort and/or performance of the wearer during the period of activity.

In one embodiment, the fluid is present within hollow chambers within the resilient material, flowing through specified orifices when pressure is applied by the user to the heel or forefoot. For example, pressure applied on the heel will force the fluid to flow forward in the shoe, towards the forefoot. Pressure on the forefoot will force the fluid to flow backwards in the shoe, towards the heel. The same method could be employed for side to side motion, fluid flowing left and right accordingly. One, more, or all, of these flow directions can be incorporated together. Accordingly, the viscosity of the fluid can be altered under electronic control. This allows the rate of fluid flow between chambers to be modulated by an electric current or magnetic field selectively applied to the fluid. The degree of the electric and/or magnetic field will impact the degree of viscosity and thus the stiffness level in the shoe. This provides electronic control of the compliance felt by the wearer of the shoe during physical activity. The current and/or magnetic field can be applied to the entire mass of fluid, or in preferred embodiments, only to the area of an orifice (or orifices) through which the fluid must flow. In such embodiments, the resilience of the shoe undersurface would be controllable as follows: When the viscosity is high, the fluid flowing from a chamber to which pressure has been applied will be slowed, and the material will therefore be less resilient (more stiff). When the viscosity is low, the fluid will flow more freely from a chamber to which pressure has been applied and the material will be more resilient (less stiff). A plurality of individually controllable E/M field generators can be used for independent control of various portions of the shoe underside. For example the heel stiffness and forefoot stiffness could be independently controlled. The control of the viscosity of electro-rheological and magneto-rheological fluids may be accomplished while consuming a low amount of power relative to the amount of stiffness modulation achieved, therefore consuming very little energy during normal operation. In another embodiment, the aforementioned bladder system 10 (or 110) can be replaced by, or supplemented with, ER or MR fluid impregnated in a foam matrix (e.g., using technology obtained from Lord Corporation). Accordingly, a foam matrix impregnated with a rheological fluid may be collectively referred to as a “rheological body.” Therefore, the stiffness of the impregnated foam matrix can be modulated using one or more of the aforementioned E/M field generators operably proximate to the impregnated foam matrix.

A cushioning system disclosed herein provides varying amounts cushioning to the wearer as well as varying amounts of resistance to front-back motion and side-to-side motion depending on the severity of such motion while walking, running, or participating in other athletic activities. Accordingly, the present invention introduces electronically controllable cushioning and electronically controllable side-to-side and front-to-back resilience using electrorheological or magnetorheological fluids within the sole of the shoe, the fluids changing their viscosity under the control of an electronic circuit based upon the changing activities and/or desires or the user. This system can therefore be controlled to provide optimum cushioning for a given activity, while simultaneously providing the needed amount of side-to-side or front-to-back motion control by stiffening a portion of the footwear in response to the individual behavior. In one embodiment, a bladder system filled with ER or MR fluid is used, the bladder system being constructed with narrow passageways surrounded by embedded electrodes and/or electromagnets. The narrow passageways act as electronically controllable flow valves under the control of an electronic circuit, the flow valves regulating the flow of the fluid from one chamber of the bladder system to another. By modulating the current flowing to the electrodes and/or electromagnets, the cushioning and/or side-to-side motion control of the shoe can be adjusted in real time to meet the changing needs of the wearer. The system provides electronically controllable comfort and control in a light weight, low power, fast responding, and very compact construction that has no moving electromechanical components such as motors that can wear out, make noise, draw too much power, and/or respond too slowly. One embodiment of the present invention utilizes lightweight bladders filled with ER or MR fluid for the dual purposes of cushioning and motion control.

An article of footwear designed accordance with one embodiment of the present invention comprises a bladder system positioned within the sole of the footwear, the bladder system housing ER fluid or MR fluid. The system includes at least first and second bladder chambers in fluid communication with each other. A first valve is positioned between the first bladder chamber and the second bladder chamber, the valve being comprised of a fluid passageway with one or more electrodes or electromagnets positioned operably proximate to (e.g., near or around) the passageway such that when the electrodes or electromagnets are energized by control electronics they impart an electric field or magnetic field respectively upon the fluid flowing through the passageway. When the fluid used in the footwear design is an ER fluid, the valve is designed using one or more electrodes that impart an electric field on the fluid moving through the passageway. When the fluid used in the footwear design is an MR fluid the valve is designed using one or more electromagnets that impart a magnetic field upon the fluid moving through the passageway. In this way the valve under electronic control of control electronics can vary the flow rate of the ER or MR fluid flowing through the passageway between the first and second bladder chamber and thereby modulate the shock cushioning and/or side-to-side support provided by footwear. In one embodiment, the control electronics include a microprocessor that runs firmware code, the firmware code controlling the current flowing to the valve to modulate the shock cushioning and/or side-to-side support provided by the sole of the shoe. In another embodiment, the footwear also includes one or more sensors connected to the microprocessor such that the activity of the wearer can be monitored during use and the cushioning and/or side-to-side support provided by the ER or MR fluid can be modulated based upon the monitored activity. In another embodiment, the microprocessor collects data from the one or more sensors and then adjusts the current to the valves in accordance with the data collected from the sensors. In another embodiment, the microprocessor is also connected to a timer or clock and uses data from the timer or clock to adjust the current to the valves. Based upon the level at which the first valve is energized, fluid will flow at a certain rate from the first bladder chamber to the second bladder chamber when pressure is applied by the wearer. This flow rate will define the effective cushioning of the sole and/or the effective side-to-side support provided by the sole to the wearer. In some embodiments, the same first valve can be used to control flow in both directions (in a first direction from the first bladder chamber to the second bladder chamber and in a second direction from the second bladder chamber to the first bladder chamber). In other embodiments a second valve can be used to control the flow in the second direction. The second valve can be a passive valve that is not electronically controlled or the second valve can be an active valve that is electronically controlled. In some embodiments, the valves are one-way valves that only allow flow in one direction. In some embodiments, more than two valves can be used, a plurality of the valves with electronic control of electrodes or electromagnets, the plurality of valves increasing the controllability of the cushioning and/or side-to-side support provided by the footwear.

In one embodiment, the bladder system housing MR or ER fluid is positioned is within a heel region of the sole and the first bladder chamber is disposed adjacent one side of the heel region, a third bladder chamber is disposed adjacent the other side of the heel region and the second bladder chamber is disposed between the first and third bladder chambers in fluid communication therewith. A first valve under electronic control is placed between the first bladder chamber and the second bladder chamber and a second valve under electronic control is positioned between the third bladder chamber and the second bladder chamber. The valves are modulated by control electronics such that fluid flows more easily from the second chamber to one of the first chamber or the third chamber. When fluid flows more easily to the first chamber, more support is shifted to that side of the heel. When fluid flows more easily to the third chamber, more support is shifted to that side of the heel. The rate of fluid flow, which can be modulated independently of the ratio between the fluid flows, controls the affects overall cushioning feel of the central heel region.

Embodiments disclosed herein also describe one or more bladder chambers in the heel region of the sole as well as one or more bladder chambers within the forefoot regions of the sole, the sole and forefoot chambers being in fluid communication with each other through electronically controllable valves as described previously. When pressure is applied to the heel region that is greater than the pressure applied to the forefoot region, fluid is forced from one or more chambers in the heel into one or more chambers in the forefoot, the rate of the flow being modulated by one or more electronically controlled valves between the heel region and the forefoot region. In this way, the stiffness of the heel can be modulated by the electronics that control the valves and thereby affect that cushioning and support on the heel of the wearer. When pressure is applied to the forefoot region that is greater than the pressure applied to the heel region, fluid is forced from one or more chambers in the forefoot into one or more chambers in the heel, the rate of the flow being modulated by one or more electronically controlled valves between the forefoot region and the heel region. In this way the stiffness of the forefoot region can be modulated by the electronics that control the valves and thereby affect the cushioning and support on the forefoot of the wearer.

In some embodiments, multiple chambers are used in the forefoot and/or heel, the multiple regions including, for example, a left region, central region, and right region, multiple electronically controllable valves used to independently vary the flow into and out of the regions thereby allowing independent control of the cushioning and support and in the regions. In this way the left, central, or right side of the heel can be made more or less stiff independently of the other regions. Similarly the left, central, or right side of the forefoot can be made more or less stiff independently of the other regions. In one embodiment, the electronic valves and chambers are positioned such that a first valve modulates flow between a left heel chamber and a left forefoot chamber, a second valve modulates flow between a central forefoot chamber and a central heel chamber, and a third valve modulates flow between a right heel chamber and a right forefoot chamber. In this embodiment, control electronics regulate the relative flow rates within all three valves to vary the forward-back and left-right cushioning and support on the foot based upon the activity of the wearer.

While embodiments have been disclosed herein by means of specific examples and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims. 

1. A variable footwear support system, comprising: at least one rheological body within a sole of an article of footwear, wherein the sole is formed of a resilient material and wherein the rheological body contains a rheological fluid having a viscosity that is variable in the presence of an energy field; control electronics adapted to generate at least one control signal; and at least one E/M field generator coupled to the control electronics and arranged operably proximate to at least one rheological body, wherein the at least one E/M field generator is adapted to generate an energy field corresponding to a control signal generated by the control electronics upon the rheological body.
 2. The variable footwear support system of claim 1, wherein at least one rheological body is within at least one of a heel region, a forefoot region, a medial region, and a lateral region of the sole of the article of footwear.
 3. The variable footwear support system of claim 1, wherein at least one rheological body comprises a bladder chamber defining a cavity adapted to contain the rheological fluid.
 4. The variable footwear support system of claim 1, wherein at least one rheological body comprises: a plurality of bladder chambers each defining a cavity adapted to contain the rheological fluid; and at least one conduit coupled to at least two of the plurality of bladder chambers such that a cavity of one of the plurality of bladder chambers is in fluid communication with a cavity of at least one other of the plurality of bladder chambers, wherein at least one E/M field generator is operably proximate to at least one conduit.
 5. The variable footwear support system of claim 1, wherein at least one rheological body includes a foam matrix impregnated with the rheological fluid.
 6. The variable footwear support system of claim 1, wherein the rheological fluid comprises electrorheological fluid and the E/M field generator comprises at least one electrode adapted to generate an electric field upon the electrorheological fluid contained within the rheological body.
 7. The variable footwear support system of claim 1, wherein the rheological fluid comprises magnetorheological fluid and the E/M field generator comprises at least one electromagnet adapted to generate a magnetic field upon magnetorheological fluid contained within the rheological body.
 8. The variable footwear support system of claim 1, further comprising at least one sensor adapted to detect at least one of an intensity and a frequency of foot-falls of the wearer of the article of footwear and generate sensor data based upon the detecting, wherein the control electronics is adapted to receive the generated sensor data and generate at least one control signal corresponding to the received sensor data.
 9. The variable footwear support system of claim 8, wherein the at least one sensor and the control electronics are within the same article of footwear.
 10. The variable footwear support system of claim 8, wherein the at least one sensor and the control electronics are within different articles of footwear.
 11. The variable footwear support system of claim 8, wherein the at least one sensor includes at least one of a pressure sensor, an accelerometer, and a contact switch.
 12. The variable footwear support system of claim 8, wherein the control electronics is further adapted to store the received sensor data.
 13. The variable footwear support system of claim 8, wherein the control electronics is further adapted to output the received sensor data to a host computer.
 14. The variable footwear support system of claim 1, further comprising a user interface coupled to the control electronics, wherein the user interface is adapted to be engaged by a wearer of the article of footwear to receive user input; and the control electronics is adapted to receive the user input and generate at least one control signal corresponding to the received user input.
 15. The variable footwear support system of claim 14, wherein the user interface is integrated within the article of footwear.
 16. The variable footwear support system of claim 14, further comprising a handheld computing device, wherein the user interface is integrated within the handheld computing device.
 17. The variable footwear support system of claim 14, wherein the handheld computing device is coupled to the control electronics via at least one of a wired connection and a wireless connection.
 18. The variable footwear support system of claim 1, wherein the control electronics is adapted to generate at least one control signal corresponding to one or more of a plurality of different physical activities of a wearer of the article of footwear, the plurality of different physical activities including at least two of walking, jogging, running, hiking, climbing stairs, playing basketball, and playing tennis.
 19. The variable footwear support system of claim 1, wherein the at least one control signal is generated at least in part upon a detected physical characteristic of the gait of a wearer of the article of footwear.
 20. The variable footwear support system of claim 19, wherein the detected physical characteristic includes at least one of a rate, a magnitude of the gait of the wearer of the article of footwear.
 21. A variable footwear support method, comprising: receiving sensor data from at least one sensor, the sensor data describing at least one of an intensity and a frequency of footfalls of a wearer of an article of footwear; generating at least one control signal based on the received sensor data; and energizing at least one E/M field generator based on the at least one generated control signal, wherein each energized E/M field generator generates an energy field upon at least one rheological body arranged within a sole of an article of footwear, wherein the sole is formed of a resilient material and wherein the at least one rheological body contains a rheological fluid having a viscosity that is variable in the presence of the generated energy field.
 22. The variable footwear support method of claim 21, wherein the at least one sensor and the at least one rheological body are within the same article of footwear.
 23. The variable footwear support method of claim 21, wherein the at least one sensor and the at least one rheological body are within different articles of footwear.
 24. A variable footwear support method, comprising: receiving user input from a user interface; generating at least one control signal based on the received user input; and energizing at least one E/M field generator based on the at least one generated control signal, wherein each energized E/M field generator generates an energy field upon at least one rheological body arranged within a sole of an article of footwear, wherein the sole is formed of a resilient material and wherein the at least one rheological body contains a rheological fluid having a viscosity that is variable in the presence of the generated energy field. 